Magnetic latch for doors



Feb. 5, 1952 J. F. MANTING MAGNETIC LATCH FOR DOORS Filed Dec. 9 1950 RC RECTIFIER -lZ V @W MZ w/ m m W7 ma V z w z Patented Feb. 5, 1952 MAGNETIC LATCH FOR DOORS Jack F. Manting, Big Rapids, Mich., assignor to Denham Manufacturing Company, Big Rapids,

Mich.

Application December 9, 1950, Serial No. 199,969

6 Claims. (Cl. 292-1) This invention relates to improvements in magnetic latch for doors.

The principal objects of this invention are:

First, to provide a novel form of electromagnetic latch structure which is particularly useful for securing refrigerator doors and the like in closed position.

Second, to provide a magnetic latch structure which will exert positive opening force on the door when the latch is released.

Third, to provide latch structure which is relatively simple and which may be entirely enclosed within the door and walls of a refrigerator, and not form a heat conductor path to the exterior of the refrigerator.

Other objects and advantages of my invention will be apparent from a consideration of the following description and claims.

The drawings, of which there is one sheet illustrate a preferred form of my latch structure.

Fig. 1 is a side el-evational view of the latch structure operatively associated with a refrigerator door, the refrigerator and door being conventionally indicated by dotted lines to better illustrate the elements of the latch.

Fig. 2 is a plan view of the latch with the refrigerator similarly and conventionally illustrated.

Fig. 3 is a circuit diagram of the electrical connections of my latch structure.

In the drawings I have illustrated a refrigerator having side walls I and 2 defining a front opening 3 to the interior of the refrigerator. A door 4 for closing the opening is hingedly connected to the wall 2 as at 5. Both the door and the walls are of the familiar thick insulated construction common in refrigerators. The particular type of door and wall construction and insulation is immaterial to the functioning of my latch and so is not illustrated in greater detail.

The swinging edge of the door 1 is provided with a recess 8 opening to the rear and interior face of the door, and the wall is provided with a similar recess 1 opposed to the recess 6. A first electromagnct 8 is positioned in the recess 6 and as illustrated includes a coil 9 and rearwardly facing U-shaped core iii. A second electromagnet II is positioned in the recess 1 and includes a coil 12 and forwardly facing U-shaped core l3. The ends of the cores l and 13 extend in opposite 2 opposed relation to the surfaces of the door 4 and the front edge of the wall I so that when the door is closed the poles or ends of the cores are brought into opposed closely adjacent and preferably contacting relationship.

Mounted in a suitable location as in the base of the refrigerator is a source of direct electrical current. This current source may conveniently be a rectifier l4 connected to the alternating current of a house by the wires 15. A transformer l6 may be provided to reduce the 110 volt house current to any desired level. The coil i2 of the electromagnet II is continuously supplied with current from the rectifier in a single direction by the conductors ll so that the poles of the core [3 are constant as illustrated.

The electromagnet 8 in the door is selectively supplied with current from the rectifier M by conductors l8 having flexible portions l9 where they enter the door. Interposed in the conductors l8 and ahead of the coil 9 is a two position reversing switch 20 which is arranged to reverse the flow of direct current through the coil 9 according to the position of the switch. The switch 20 is conveniently and desirably mounted in the top of a door pull handle 2| so that the button 22 of the switch can be easily pressed or actuated with the thumb when the handle is grasped. The switch 20 and button 21 are desirably biased outwardly of the door by a spring 23 to urge the switch 20 into a position which will energize the coil 9 oppositely from the coil i 2 so that the north pole of the core l3 opposes the south pole of the core I0 and vice versa.

With the electromagnets opposedly energized and the cores opposedly magnetized the two magnets are attracted to each other and will effectively latch or look the door in closed position. If the switch 23 is then reversed as by pressing on the button 22 the reversal of the magnetization of core ID will not only release the magnetic latch but the poles of the two cores will then positively repel each other imparting an opening force to the door.

While I have described my latch as being particularly advantageous in combination with a refrigerator, it may obviously be used in combination with other doors or closures. The door may be closed tightly without slamming and with very little noise as there is no latch spring to overcome. Very little effort is required to close the door as the electromagnets may be made of suificient strength to draw the door to closed position against the compression of any deformable sealing gaskets around the door opening once the door has been swung to partly closed position against the gaskets. The latch and door are easily opened as again there is no latch spring to overcome other than the bias spring for the button 22 which may be extremely light. The self-opening or repulsion feature of the door and latch permits the door to be opened in part by simply pressing the button 22 with the back or" the hand, which is a desirable ieature when a person approaches the reirigerator with both hands full. Since no metallic parts need to extend between the inner and outer surface of the door there is no possibility of the latch forming a heat conducting path for the now of heat into the refrigerator.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. Magnetic latch structure for a refrigerator door comprising, afirst electromagnet mounted within a wall of said refrigerator and including coil and a core having poles projecting to the front surface of said wall, a second electromagnet mounted within said door and including a secand coil and a second core with poles projecting to the baclr surface of the (100): to oppose and touch the poles of said first core when said door closed, a rectifier constituting a source of direct current mounted in said refrigerator and connectable to a source of electric power, conductors connecting said source to said first coil for constant energization and polarization of said 1" st core, other conductors including flexible portions extending to said door and connecting said second coil to said source, a handle on said door, and a switch of the two position reversing type mounted on said door and having a biased control element extending through the upper portion of said handle, said switch being interposed in and electrically connected to said other conductors to reverse the energization of said second coil and the polarization of said second core whereby the poles of said second core will be repelled from the poles of said first core when control element is depressed.

2. Magnetic latch structure for a refrigerator.

door comprising, a first electromagnet mounted within a wall of said refrigerator and including a coil and a core having poles projecting toward the front surface of said wall, a second electroniagnet mounted within said door and including a second coil and a second core with poles projecting toward the back surface of the door to oppose the poles of said first core when said door is closed, a source of direct current mounted in said refrigerator, conductors connecting said source to said first coil for constant energization and polarization of said first core, other condu"- tors including flexible portions extending to s "r. door and connecting said second coil to said source, a handle on said door, and a switch of the two position reversing type mounted on sai door and having a biased control element extending through the upper portion of said handle, said switch being interposed. in and electrically connected to said other conductors to reverse ixation of said second coil and the polarizaof said second core whereby the poles of s core will be repelled from the poles of said core when said control element is depressed Magnetic latch structure for the door of a. cabinet comprising, a first electromagnet mounted within a wall or said cabinet and incluclmg a coil and a core having poles pro ecting to adacent the front surrace 01' said wall, a second lectromagnet mounted Within said door and including a second coil and a second core with poles projecting to adjacent the back surface of the door to oppose the poles or said first core when said door is closed, a source oi direct current in said cabinet, conductors connecting said source to said first coil for constant energization and polarization of said first core, other conductors connecting said second coil to said source, a handle on said door, and a switch of the two position reversing type mounted on said door and having a biased control element extending t ough the upper portion of said handle, said switch being interposed in and electrically connected to said other conductors to reverse the energization of said second coil and the polarization 01' said second core whereby the poles of said second core will be repelled from the poles of said first core when said control element is depressed.

i. Magnetic latch structure for the door of a abinet comprising, a first electromagnct mount- 01 within a wall of said cabinet and including coil and a core having poles projecting to adacent the front surface of said wall, a sec- 5 d electromagnet mounted within said door and including a second coil and a second core with poles projecting to adjacent the back surlace oi the door to oppose the poles of said first core when said door is closed, a source of direct current in said cabinet, conductors connecting source to said first coil for constant energiza n and polarization of said first core, other conductors connecting said second coil to said source. a handle on said door, and a switch of the two position reversing type mounted on said door and having a biased control element positioned adjacent to said handle, said switch being interposed in and electrically connected to said other conductors to reverse the energization of said second coil and the polarization of said second core whereby the poles of said second core will be repelled from the poles of said first core when said control element is actuated.

5. Magnetic latch structure for a door of a cabinet comprising, first electromagnet mounted on a wall of said cabinet and including a coil and a core having poles projecting to adjacent the front surface of said cabinet, a second electromagnet mounted on said door and including a second coil and a second core with poles projecting to adjacent the back surface of the door to oppose the poles of said first core when said door is closed, a source of direct current in said cabinet, conductors connecting said source to one of said coils for constant energization and polarization of its core, other conductors connecting the other of said coils to said source, a handle on said door, and a switch of the two position reversing type mounted on said door and having a biased control element positioned adjacent to said handle, said switch being interposed in and electrically connected to said other conductors to reverse the energization of said other coil and the polarization of its core whereby the poles of said other core will be repelled from the poles of said one core when said control element is actuated.

6. Magnetic latch structure for a door of a cabinet comprising, first electromagnet mounted on a wall of said cabinet and including a coil and a core having poles projecting to adjacent the front surface of said cabinet, a second electromagnet mounted on said door and including a second coil and a second core with poles projecting to adjacent the back surface of the door to oppose the poles of said first core when said door is closed, a source of direct current in said cabinet, conductors connecting said source to one of said coils for constant energization and polarization of its core, other conductors connecting the other of said coils to said source, and a switch of the two position reversing type mounted on said cabinet and having a biased control element, said switch being interposed in 15 2,253,252

6 and electrically connected to said other conductors to reverse the energization of said other coil and the polarization of its core whereby the poles of said other core will be repelled from the poles of said one core when said control element is actuated.

JACK F. MAN'I'ING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Smith Aug. 19, 1941 Number 

